Topic 3: Nodal and Mesh Analysis

Question 1

For mesh analysis, if the circuit contains current sources, what can we do to form a super mesh?

Answer 1

Replacing each current source with a short circuit to form super meshes.

Question 2

For nodal analysis, if the circuit contains voltage sources, what can we do to form super meshes?

Answer 2

Replacing each voltage source by an open-circuit.

Question 3

What is the method for conducting mesh analysis?

Answer 3

1. Identify mesh and define mesh currents
2. Construct equations in each mesh, usually using KVL (if KVL cannot be used due to current sources, conduct KVL around a larger loop that excludes the current source)
3. Write equations in standard form (1 coefficient for each unknown = constant)
4. Solve equation set using matrices or simultaneous equations

Question 4

When conducting node analysis, for resistors, what is the assumed direction?

Answer 4

For nodal analysis, resistors are treated as if the current is exiting the node.

Question 5

What is special case 1 for nodal analysis?

Answer 5

Special case 1 for nodal analysis is where there is a voltage source connected to 1 unknown node.

Question 6

How do you deal with special case 1 when conducting nodal analysis?

Answer 6

You evaluate the voltage difference between the unknown node and the reference node.

Vb = V1 - 0 
V1 = Vb

Question 7

What is a planar circuit?

Answer 7

A planar circuit is a circuit that can be drawn such that no branch passes over or under another branch.

Question 8

What is a loop?

Answer 8

A loop is any closed path.

i.e. the first node is the same as the final node

Question 9

What is a mesh?

Answer 9

A mesh is a loop that doesn’t contain any smaller loops within it.

Question 10

What is a mesh current?

Answer 10

A mesh current is a mathematical current which charge flows only around the perimeter of a mesh.

Question 11

How is a mesh current indicated?

Answer 11

A mesh current is indicated by a curved arrow